I need to renew my tags, and last time I checked, I had an O2 sensor error that I've just been putting off.

I went to Autozone and had the truck retested today and got an error: P1518 which indicates a IMRC stuck open. I have located the IMRC cable and what I 'think' is the white clip everyone seems to suggest can break off and cause this issue and that seems fine. I removed the plastic housing that covers the cable and did notice it has some give to it, but I couldn't begin to tell you if it's normal or not.

So, the actual IMRC actuator, I'm told, is behind the firewall.

I really don't want this to be a spend hundreds to find the problem scenario and realize it can be a myriad of things, so I thought I'd post my issue here. Does anyone have experience with this and can point me in some troubleshooting directions?

I have noted a lack of horsepower at higher speeds but had attributed this to the truck being old. Maybe it's the actuator not doing it's job at higher RPMs?

Here is a two page post someone made showing how to remove the upper intake which you have to do to work on the IMRC. On page 2, step 46 is another link which will take you to another write up showing the IMRC and what needs to be done to fix them.

The BEST write up and pictures I've found showing how to do them!

My 2003 4.2 threw the code last year for the first time. I ran Sea Foam through the engine, disconnected the battery, and the light stayed off for over a year. Just last week it came back on. I disconnected the battery, and again so far the light has stayed off. I am just putting off the inevitable, as I know I will have to repair these sooner or later. But I am not going to pay $800.00 at the dealership to get this done! That's why I bookmarked that write up last year.